uniform sampler3D dataTex;
uniform sampler1D cmapTex;
void main()
{
	vec4 den = texture3D(dataTex, gl_TexCoord[0].xyz);
	if(den.s == 0.0) {
	 gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);
	} else {
	 	vec4 clr = texture1D(cmapTex, den.s);
		gl_FragColor = clr;
	}
	// gl_FragColor = vec4(0.0, 0.0, 0.7, 0.5);
}